Police find three bodies in northern Mexico

The man had been shot in the head and his body dumped in a residential area and set ablaze, said Eduardo Anaya, an investigator with Tamaulipas state, which includes Nuevo Laredo. The man is the 12th person slain and burned since the beginning of the year in Nuevo Laredo, a city of 300,000 across from Laredo, Texas, where more than 100 people have been killed since January.

This sprawling border city has seen an increase in drug-related killings after the region's alleged drug lord, Osiel Cardenas, was arrested in 2003 during a shootout in Matamoros, across from Brownsville, Texas. Authorities say the violence has intensified in recent months because another reputed drug lord, Joaquin "El Chapo" Guzman, has been fighting smugglers loyal to Cardenas to gain access to prized smuggling routes into the United States.

On Sunday, police in the city of Guadalupe, 135 miles (220 kilometers) southeast of Nuevo Laredo, found the bodies of two men who had been shot in the head and dumped in an alley. Mexican news media reported that one of the men was Lucio Manriquez Martinez, one of Guzman's operatives in Nuevo Laredo, AP reports.